WO2024210537A1 - Apparatus and method for setting power of prach repeated transmission in wireless communication system - Google Patents

Abstract

According to various embodiments of the present disclosure, provided is an operating method of a user equipment (UE) in a wireless communication system, comprising the steps of: receiving, from a base station (BS), radio resource control (RRC) information related to the maximum number of random access (RA) preamble repetitions, corresponding to a first number of times; performing, in relation to a first RA procedure, first repeated transmission of an RA preamble to the BS on the basis of the first number of times; if the first repeated transmission of the RA preamble based on the first number of times is performed and the first RA procedure is not completed, determining the number of RA preamble repeated transmissions on the basis of a second number of times that is greater than the first number of times; and performing, in relation to a second RA procedure, second repeated transmission of the RA preamble to the BS on the basis of the second number of times.

Description

Device and method for setting power of PRACH repetitive transmission in wireless communication system

The present disclosure relates to a wireless communication system. Specifically, the present disclosure relates to an apparatus and method for setting power of a PRACH repetitive transmission in a wireless communication system.

NR supports multiple numerologies (or subcarrier spacings (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, it supports wide area in traditional cellular bands, when the SCS is 30 kHz/60 kHz, it supports dense-urban, lower latency, and wider carrier bandwidth, and when the SCS is 60 kHz or higher, it supports bandwidths greater than 24.25 GHz to overcome phase noise.

Various RAN1 work items define how to distinguish between terminal/base station operations based on RACH resources (e.g., PRACH preamble index, etc.). For example, terminals related to redcap, small data transmission, Msg. 3 PUSCH repetition, etc. are defined to select a specific preamble index and request the base station to use the corresponding feature during the PRACH preamble transmission phase. However, if operations created separately for each WI are defined in the spec, it can become complicated.

Therefore, in order to efficiently support terminal/base station operations that require distinction using RACH resources (e.g., PRACH preamble index, etc.) in the RAN2 Rel-17 RACH partitioning work item, the concept of “Feature Combination” was introduced. That is, the base station notifies the terminal that a specific feature or a specific combination of features is supported by setting a specific PRACH resource (e.g., preamble start index and total number indication), and the terminal that wants to use/request a specific feature and/or specific combination of features can select one of the preamble indexes of the area allocated with the specific feature and/or specific combination of features desired by the terminal during the RACH procedure and transmit the PRACH preamble.

Specifically, the FeatureCombinationPreambles parameter can be set multiple times in RACH-ConfigCommon, and the preamble index sections corresponding to each area need to be set so as not to overlap. In addition, the features and/or combinations of features set in each area need to be set so as not to overlap each other.

In addition to the RACH-ConfigCommon assigned to the existing BWP-UplinkCommon, the base station can additionally assign RACH configuration through AdditionalRACH-Config-r17. As a result, Rel-16 terminals that cannot read AdditionalRACH-Config-r17 will perform the RACH procedure by looking at the RACH-ConfigCommon assigned to the existing BWP-UplinkCommon, but Rel-17 and later terminals that can read AdditionalRACH-Config-r17 will perform the RACH procedure by checking the RACH-ConfigCommon assigned to AdditionalRACH-Config-r17 in addition to the RACH-ConfigCommon assigned to the existing BWP-UplinkCommon. In addition, one or more of the FeatureCombinationPreambles described above can be set to RACH-ConfigCommon allocated to the existing BWP-UplinkCommon, and one or more of the FeatureCombinationPreambles described above can be set to RACH-ConfigCommon allocated to AdditionalRACH-Config-r17. The RRC parameters related to the RACH partitioning can be expressed in a diagram as in Figure 3-0.

Meanwhile, we are considering introducing PRACH preamble repetition transmission for UL coverage enhancement of the existing NR system. Therefore, in order to support PRACH repetition, we need to define how to allocate between PRACH resources with different repetition transmission counts. As a simple method, we can consider a method of allocating RACH resources so that they are distinguished by preamble level or RO level among multiple PRACH repetition resources with different repetition transmission counts.

To solve the above-mentioned problems, the present disclosure provides a device and method for setting the power of PRACH repetitive transmission in a wireless communication system.

The present disclosure provides an apparatus and method for performing an operation related to a case where the same repetition number is allocated among a plurality of PRACH repetition resources in a wireless communication system.

The technical problems to be achieved in the present disclosure are not limited to the technical problems mentioned above, and other technical problems not mentioned will be clearly understood by a person having ordinary skill in the technical field to which the present disclosure belongs from the description below.

According to various embodiments of the present disclosure, a method for operating a user equipment (UE) in a wireless communication system is provided, the method comprising: receiving, from a base station (BS), RRC (radio resource control) information related to a maximum number of repetitions of a random access (RA) preamble corresponding to a first number of times; performing a first repeated transmission of an RA preamble to the BS based on the first number of times in relation to a first RA procedure; determining a number of repeated transmissions of the RA preamble based on a second number of times greater than the first number of times when the first repeated transmission of the RA preamble based on the first number of times is performed and the first RA procedure is not completed; and performing a second repeated transmission of the RA preamble to the BS based on the second number of times in relation to a second RA procedure.

According to various embodiments of the present disclosure, a method for operating a base station (BS) in a wireless communication system is provided, comprising: transmitting, to a user equipment (UE), RRC (radio resource control) information related to a maximum number of repetitions of a random access (RA) preamble corresponding to a first number of times; receiving, in relation to a first RA procedure, a first repeated transmission of an RA preamble from the UE based on the first number of times; and, if the first repeated transmission of the RA preamble based on the first number of times is performed and the first RA procedure is not completed, receiving, in relation to a second RA procedure, a second repeated transmission of the RA preamble from the BS based on a second number of times, wherein the second number of times is a number of repeated transmissions of the RA preamble that is greater than the first number of times.

According to various embodiments of the present disclosure, in a wireless communication system, a terminal is provided, comprising: a transceiver, at least one processor, and at least one memory operably connectable to the at least one processor and storing instructions that, when executed by the at least one processor, perform operations, wherein the operations include all steps of a method of operating the terminal according to various embodiments of the present disclosure.

According to various embodiments of the present disclosure, in a wireless communication system, a base station is provided, comprising: a transceiver, at least one processor, and at least one memory operably connectable to the at least one processor and storing instructions that, when executed by the at least one processor, perform operations, wherein the operations include all steps of a method of operating the base station according to various embodiments of the present disclosure.

According to various embodiments of the present disclosure, a control device for controlling a terminal in a wireless communication system is provided, comprising at least one processor and at least one memory operably connected to the at least one processor, wherein the at least one memory stores instructions for performing operations based on being executed by the at least one processor, the operations including all steps of a method of operating the terminal according to various embodiments of the present disclosure.

According to various embodiments of the present disclosure, a control device for controlling a base station in a wireless communication system is provided, comprising at least one processor and at least one memory operably connected to the at least one processor, wherein the at least one memory stores instructions for performing operations based on being executed by the at least one processor, the operations including all steps of a method of operating the base station according to various embodiments of the present disclosure.

According to various embodiments of the present disclosure, a computer-readable medium is provided storing one or more non-transitory computer-readable media having one or more instructions, wherein the one or more instructions perform operations based on being executed by one or more processors, the operations including all steps of a method of operating a terminal according to various embodiments of the present disclosure.

According to various embodiments of the present disclosure, a computer-readable medium storing one or more non-transitory instructions, wherein the one or more instructions perform operations based on execution by one or more processors, wherein the operations include all steps of a method of operating a base station according to various embodiments of the present disclosure.

To solve the above-described problems, the present disclosure can provide a device and method for setting the power of PRACH repetitive transmission in a wireless communication system.

The present disclosure may provide for performing operations related to a case where the same repetition number is allocated among a plurality of PRACH repetition resources in a wireless communication system.

The drawings attached below are intended to aid in understanding the present disclosure and may provide embodiments of the present disclosure together with detailed descriptions. However, the technical features of the present disclosure are not limited to specific drawings, and the features disclosed in each drawing may be combined with each other to form a new embodiment. Reference numerals in each drawing may mean structural elements.

FIG. 1 is a diagram illustrating an example of physical channels used in a system applicable to the present disclosure and a general signal transmission method using the same.

FIG. 2 is a diagram illustrating an example of a wireless frame structure used in a system applicable to the present disclosure.

FIG. 3 is a drawing illustrating an example of a slot structure used in a system applicable to the present disclosure.

FIG. 4 is a diagram illustrating an example of a slot structure of a wireless frame used in a system applicable to the present disclosure.

FIG. 5 is a diagram illustrating an example of RRC parameters related to RACH partitioning in a system applicable to the present disclosure.

FIG. 6 is a diagram illustrating an example of an operation process of a terminal in a system applicable to the present disclosure.

FIG. 7 is a diagram illustrating an example of an operation process of a base station in a system applicable to the present disclosure.

FIG. 8 is a drawing illustrating an example of the structure of a first device and a second device in a system applicable to the present disclosure.

In various embodiments of the present disclosure, “A or B” can mean “only A,” “only B,” or “both A and B.” In other words, in various embodiments of the present disclosure, “A or B” can be interpreted as “A and/or B.” For example, in various embodiments of the present disclosure, “A, B or C” can mean “only A,” “only B,” “only C,” or “any combination of A, B and C.”

In various embodiments of the present disclosure, a slash (/) or a comma may mean "and/or". For example, "A/B" may mean "A and/or B". Accordingly, "A/B" may mean "only A", "only B", or "both A and B". For example, "A, B, C" may mean "A, B, or C".

In various embodiments of the present disclosure, “at least one of A and B” can mean “only A,” “only B,” or “both A and B.” Furthermore, in various embodiments of the present disclosure, the expressions “at least one of A or B” or “at least one of A and/or B” can be interpreted as equivalent to “at least one of A and B.”

Additionally, in various embodiments of the present disclosure, “at least one of A, B and C” can mean “only A,” “only B,” “only C,” or “any combination of A, B and C.” Additionally, “at least one of A, B or C” or “at least one of A, B and/or C” can mean “at least one of A, B and C.”

In addition, the parentheses used in various embodiments of the present disclosure may mean "for example". Specifically, when indicated as "control information (PDCCH)", "PDCCH" may be proposed as an example of "control information". In other words, the "control information" of various embodiments of the present disclosure is not limited to "PDCCH", and "PDDCH" may be proposed as an example of "control information". In addition, even when indicated as "control information (i.e., PDCCH)", "PDCCH" may be proposed as an example of "control information".

Technical features that are individually described in a single drawing in various embodiments of the present disclosure may be implemented individually or simultaneously.

Common signal transmission methods in 3GPP

Physical channels and general signal transmission

FIG. 1 is a diagram illustrating an example of physical channels used in a system applicable to the present disclosure and a general signal transmission method using the same. Specifically, FIG. 1 exemplifies physical channels used in a 3GPP system and general signal transmission.

Figure 1 illustrates physical channels and general signal transmission used in a 3GPP system. In a wireless communication system, a terminal receives information from a base station through a downlink (DL), and the terminal transmits information to the base station through an uplink (UL). The information transmitted and received by the base station and the terminal includes data and various control information, and various physical channels exist depending on the type/purpose of the information they transmit and receive.

When a terminal is powered on again from a powered-off state or enters a new cell, it performs an initial cell search operation such as synchronizing with the base station (S11). To this end, the terminal receives a PSCH (Primary Synchronization Channel) and an SSCH (Secondary Synchronization Channel) from the base station to synchronize with the base station and obtain information such as a cell ID (cell identity). In addition, the terminal can receive a PBCH (Physical Broadcast Channel) from the base station to obtain broadcast information within the cell. In addition, the terminal can receive a DL RS (Downlink Reference Signal) during the initial cell search phase to check the downlink channel status.

A terminal that has completed initial cell search can obtain more specific system information by receiving a PDCCH (Physical Downlink Control Channel) and a corresponding PDSCH (Physical Downlink Control Channel) (S12).

Thereafter, the terminal can perform a random access procedure to complete connection to the base station (S13 to S16). Specifically, the terminal can transmit a preamble through a PRACH (Physical Random Access Channel) (S13) and receive a RAR (Random Access Response) for the preamble through a PDCCH and a PDSCH corresponding thereto (S14). Thereafter, the terminal can transmit a PUSCH (Physical Uplink Shared Channel) using scheduling information in the RAR (S15) and perform a contention resolution procedure such as a PDCCH and a PDSCH corresponding thereto (S16).

The terminal that has performed the procedure as described above can then perform PDCCH/PDSCH reception (S17) and PUSCH/PUCCH (Physical Uplink Control Channel) transmission (S18) as general uplink/downlink signal transmission procedures. The control information that the terminal transmits to the base station is referred to as UCI (Uplink Control Information). UCI includes HARQ ACK/NACK (Hybrid Automatic Repeat and reQuest Acknowledgement/Negative-ACK), SR (Scheduling Request), CSI (Channel State Information), etc. CSI includes CQI (Channel Quality Indicator), PMI (Precoding Matrix Indicator), RI (Rank Indication), etc. UCI is generally transmitted through PUCCH, but can be transmitted through PUSCH when control information and data need to be transmitted simultaneously. In addition, the terminal can aperiodically transmit UCI through PUSCH according to a request/instruction of the network.

OFDM (Orthogonal Frequency Division Multiplexing) Numerology

The new RAT system uses OFDM transmission scheme or similar transmission scheme. The new RAT system may follow OFDM parameters different from those of LTE. Or, the new RAT system may follow the existing numerology of LTE/LTE-A but have a larger system bandwidth (e.g., 100MHz). Or, a single cell may support multiple numerologies. That is, UEs operating with different numerologies may coexist in a single cell.

Radio frame structure

FIG. 2 is a diagram illustrating an example of the structure of a wireless frame used in a system applicable to the present disclosure.

In NR, uplink and downlink transmissions are organized into frames. A radio frame has a length of 10 ms and is defined by two 5 ms half-frames (Half-Frames, HF). A half-frame is defined by five 1 ms subframes (Subframes, SF). A subframe is divided into one or more slots, and the number of slots in a subframe depends on the Subcarrier Spacing (SCS). Each slot contains 12 or 14 OFDM (A) symbols depending on the cyclic prefix (CP). When normal CP is used, each slot contains 14 symbols. When extended CP is used, each slot contains 12 symbols. Here, a symbol may include an OFDM symbol (or a CP-OFDM symbol), an SC-FDMA symbol (or a DFT-s-OFDM symbol).

Table 1 illustrates that when CP is normally used, the number of symbols per slot, the number of slots per frame, and the number of slots per subframe vary depending on the SCS.

SCS (15*2^u) N ^slot _symb N ^frame,u _slot N ^subframe,u _slot 15KHz (u=0) 14 10 1 30KHz (u=1) 14 20 2 60KHz (u=2) 14 40 4 120KHz (u=3) 14 80 8 240KHz (u=4) 14 160 16

N ^slot _symb is the number of symbols in a slot. N ^frame,u _slot is the number of slots in a frame. N ^subframe,u _slot is the number of slots in a subframe.

Table 2 illustrates that when extended CP is used, the number of symbols per slot, the number of slots per frame, and the number of slots per subframe change depending on the SCS.

SCS (15*2^u) N ^slot _symb N ^frame,u _slot N ^subframe,u _slot 60KHz (u=2) 12 40 4

NR supports multiple numerologies (or subcarrier spacings (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, it supports wide area in traditional cellular bands, when the SCS is 30 kHz/60 kHz, it supports dense-urban, lower latency, and wider carrier bandwidth, and when the SCS is 60 kHz or higher, it supports bandwidths greater than 24.25 GHz to overcome phase noise.

The NR frequency band can be defined by two types of frequency ranges (FR1, FR2). The numerical values of the frequency ranges can be changed, and for example, the two types of frequency ranges (FR1, FR2) can be as shown in Table 3 below. For convenience of explanation, among the frequency ranges used in the NR system, FR1 can mean "sub 6GHz range", and FR2 can mean "above 6GHz range" and can be called millimeter wave (mmW).

Frequency Range designation Corresponding frequency range Subcarrier Spacing FR1 450MHz - 6000MHz 15, 30, 60kHz FR2 24250MHz - 52600MHz 60, 120, 240kHz

As described above, the numerical value of the frequency range of the NR system can be changed. For example, FR1 can include a band of 410 MHz to 7125 MHz as shown in Table 4 below. That is, FR1 can include a frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher. For example, the frequency band of 6 GHz (or 5850, 5900, 5925 MHz, etc.) or higher included in FR1 can include an unlicensed band. The unlicensed band can be used for various purposes, for example, it can be used for communication for vehicles (e.g., autonomous driving).

Frequency Range designation Corresponding frequency range Subcarrier Spacing FR1 410MHz - 7125MHz 15, 30, 60kHz FR2 24250MHz - 52600MHz 60, 120, 240kHz

In an NR system, OFDM(A) numerology (e.g., SCS, CP length, etc.) may be set differently between multiple cells that are merged into one terminal. Accordingly, the (absolute time) section of a time resource (e.g., SF, slot, or TTI) (conveniently, collectively called TU (Time Unit)) consisting of the same number of symbols may be set differently between the merged cells.

FIG. 3 is a drawing illustrating an example of a slot structure used in a system applicable to the present disclosure.

A slot contains multiple symbols in the time domain. For example, in the case of a normal CP, one slot contains 7 symbols, but in the case of an extended CP, one slot contains 6 symbols. A carrier contains multiple subcarriers in the frequency domain. An RB (Resource Block) is defined as multiple (e.g., 12) consecutive subcarriers in the frequency domain. A BWP (Bandwidth Part) is defined as multiple consecutive (P)RBs in the frequency domain, and can correspond to one numerology (e.g., SCS, CP length, etc.). A carrier can contain up to N (e.g., 5) BWPs. Data communication is performed through activated BWPs, and only one BWP can be activated for one terminal. Each element in the resource grid is referred to as a Resource Element (RE), and one complex symbol can be mapped to it.

FIG. 4 is a diagram illustrating an example of a slot structure of a wireless frame used in a system applicable to the present disclosure.

Figure 4 is an exemplary system, illustrating the slot structure of a frame of an NR system.

The frame structure of NR is characterized by a self-contained structure in which a DL control channel, DL or UL data, and UL control channel can all be included in a single slot unit, as shown in the example of FIG. 4. At this time, DL data scheduling information, UL data scheduling information, etc. can be transmitted in the DL control channel, and ACK/NACK information for DL data, CSI information (modulation and coding scheme information, MIMO transmission-related information, etc.), scheduling request, etc. can be transmitted in the UL control channel. In FIG. 4, a time gap for DL-to-UL or UL-to-DL switching may exist between the control region and the data region. In addition, some of DL control / DL data / UL data / UL control may not be configured in a single slot. Or, the order of each channel configuring a single slot may be different. (For example, DL control / DL data / UL control / UL data or UL control / UL data / DL control / DL data, etc.)

Composition and Method of the Invention

NR supports multiple numerologies (or subcarrier spacings (SCS)) to support various 5G services. For example, when the SCS is 15 kHz, it supports wide area in traditional cellular bands, when the SCS is 30 kHz/60 kHz, it supports dense-urban, lower latency, and wider carrier bandwidth, and when the SCS is 60 kHz or higher, it supports bandwidths greater than 24.25 GHz to overcome phase noise.

Various RAN1 work items define how to distinguish between terminal/base station operations based on RACH resources (e.g., PRACH preamble index, etc.). For example, terminals related to redcap, small data transmission, Msg. 3 PUSCH repetition, etc. are defined to select a specific preamble index and request the base station to use the corresponding feature during the PRACH preamble transmission phase. However, if these operations created separately for each WI are defined in the 3GPP standard specifications, it can become complicated.

Therefore, in order to efficiently support terminal/base station operations that require distinction using RACH resources (e.g., PRACH preamble index, etc.) in the RAN2 Rel-17 RACH partitioning work item, the concept of "Feature Combination" was introduced. That is, the base station notifies the terminal that a specific feature or a specific combination of features is supported by setting a specific PRACH resource (e.g., preamble start index and total number indication), and the terminal that wants to use/request a specific feature and/or specific combination of features can select one of the preamble indexes of the area allocated with the specific feature and/or specific combination of features it wants during the RACH procedure and transmit the PRACH preamble. The RRC parameters for this operation are defined in "FeatureCombinationPreambles" and "FeatureCombination" of 3GPP TS (technical specification) 38.331.

The following [Table 5] shows the "FeatureCombinationPreambles" of 3GPP TS 38.331. The following [Table 6] shows the "FeatureCombination" of 3GPP TS 38.331.

FeatureCombinationPreambles-r17 ::= SEQUENCE {
featureCombination-r17 FeatureCombination-r17,
startPreambleForThisPartition-r17 INTEGER(1..64);
numberOfPreamblesPerSSB-ForThisPartition-r17 INTEGER (1..64);
ssb-SharedRO-MaskIndex-r17 INTEGER (1..15) OPTIONAL, -- Need S
groupBconfigured-r17 SEQUENCE {
ra-SizeGroupA-r17 ENUMERATED {b56, b144, b208, b256, b282, b480, b640, b800, b1000, b72, spare6, spare5, spare4, spare3, spare2, spare1},
messagePowerOffsetGroupB ENUMERATED { minusinfinity, dB0, dB5, dB8, dB10, dB12, dB15, dB18},
numberOfRA-PreamblesGroupA INTEGER (1..64)
} OPTIONAL, -- Need S
separateMsgA-PUSCH-Config-r17 MsgA-PUSCH-Config-r16 OPTIONAL, -- Cond MsgAConfigCommon
msgA-RSRP-Threshold-r17 RSRP-Range OPTIONAL, -- Need R
rsrp-ThresholdSSB-r17 RSRP-Range OPTIONAL, -- Need R
deltaPreamble-r17 INTEGER (-1..6) OPTIONAL, -- Need R
...
}

FeatureCombination-r17 ::= SEQUENCE {
redCap-r17 ENUMERATED {true} OPTIONAL, -- Need R
smallData-r17 ENUMERATED {true} OPTIONAL, -- Need R
nsag-r17 NSAG-List-r17 OPTIONAL, -- Need R
msg3-Repetitions-r17 ENUMERATED {true} OPTIONAL, -- Need R
spare4 ENUMERATED {true} OPTIONAL, -- Need R
spare3 ENUMERATED {true} OPTIONAL, -- Need R
spare2 ENUMERATED {true} OPTIONAL, -- Need R
spare1 ENUMERATED {true} OPTIONAL -- Need R
}

Specifically, the FeatureCombinationPreambles parameter can be set multiple times in RACH-ConfigCommon, and the preamble index sections corresponding to each area need to be set so as not to overlap. In addition, the features and/or combinations of features set in each area need to be set so as not to overlap each other.

FIG. 5 is a diagram illustrating an example of RRC parameters related to RACH partitioning in a system applicable to the present disclosure.

Meanwhile, the base station can additionally allocate RACH configuration through AdditionalRACH-Config-r17 in addition to RACH-ConfigCommon allocated to the existing BWP-UplinkCommon. As a result, Rel-16 terminals that cannot read AdditionalRACH-Config-r17 perform the RACH procedure by looking at RACH-ConfigCommon allocated to the existing BWP-UplinkCommon, but Rel-17 and later terminals that can read AdditionalRACH-Config-r17 perform the RACH procedure by checking RACH-ConfigCommon allocated to AdditionalRACH-Config-r17 in addition to RACH-ConfigCommon allocated to the existing BWP-UplinkCommon. In addition, one or more of the above-described FeatureCombinationPreambles can be set for RACH-ConfigCommon allocated to the existing BWP-UplinkCommon, and one or more of the above-described FeatureCombinationPreambles can be set for RACH-ConfigCommon allocated to AdditionalRACH-Config-r17. Fig. 5 shows an example of a graphical representation of the RRC parameters related to the RACH partitioning.

Meanwhile, introduction of PRACH preamble repetition transmission is being considered for UL coverage enhancement of the existing NR system. Therefore, in order to support PRACH repetition, it is necessary to define how to allocate between PRACH resources having different numbers of repetition transmissions. As a simple method, a method of allocating RACH resources so that they are distinguished by preamble level or RO level between multiple PRACH repetition resources having different numbers of repetition transmissions can be considered. In this case, the present disclosure proposes terminal operations and/or base station operations related to a case where the same repetition number is allocated between multiple PRACH repetition resources.

1. PRACH transmit power control method when the same repetition number is assigned to multiple RACH configurations (and/or multiple RACH partitionings)

Among several methods for allocating PRACH repetition resources having different numbers of repetition transmissions, a method for allocating RACH resources so that they are distinguished by a preamble level or a RO level among multiple PRACH repetition resources having different numbers of repetition transmissions can be considered. At this time, if the same repetition number is allocated among multiple PRACH repetition resources, a UE can perform a RACH procedure using a PRACH resource corresponding to a specific RACH configuration and then perform a RACH procedure using a PRACH resource corresponding to another RACH configuration at a pre-arranged time point. At this time, the following suggestions are made regarding when the pre-arranged time point is to be set and/or how the PRACH transmit power to be used by the UE at that time is to be set.

As a first proposed method, it can be defined that before the UE selects a PRACH repetition resource corresponding to a specific RACH configuration (and/or a specific RACH partitioning) and finishes transmitting all RACH attempts, it cannot select a PRACH repetition resource corresponding to another RACH configuration (or another RACH partitioning). In more detail, after the UE performs all RACH attempts and then fails to receive a RAR from the base station, the UE may be allowed to select one of arbitrary RACH configurations (and/or arbitrary RACH partitionings) regardless of the previously selected RACH configuration information.

At this time, the point in time when all RACH attempts have been transmitted means when the higher layer parameter "PREAMBLE_TRANSMISSION_COUNTER" value, which counts the number of RACH attempts, becomes greater than the higher layer parameter "preambleTransMax" value, which indicates the maximum number of RACH attempts. In other words, the "PREAMBLE_TRANSMISSION_COUNTER" value increases by 1 for each RACH attempt, and if this value becomes greater than the "preambleTransMax" value (expressed as if PREAMBLE_TRANSMISSION_COUNTER = preambleTransMax + 1 for 38.321), it can be viewed as the point in time when all RACH attempts have been transmitted.

Additionally, the terminal can be defined to reset the repetition number at the point in time when it has completed transmitting the entire RACH attempt. That is, the terminal can re-measure the RSRP at that point in time to reset the repetition number, or the terminal can be defined to increase the repetition number because it has not received an RAR after transmitting the entire RACH attempt.

If the repetition number to be used by the terminal does not increase, the RACH procedure can be performed in the newly selected RACH configuration by reusing the PRACH transmit power value most recently used in the previous RACH procedure. In this case, since the terminal transmits using the maximum transmit power from the first RACH attempt, power ramping between RACH attempts can be configured not to be performed.

On the other hand, if the repetition number to be used by the terminal increases, the RACH procedure can be performed in the newly selected RACH configuration based on the PRACH transmit power used in the previous RACH procedure (with the corresponding value set as the PRACH transmit power of the initial RACH attempt). In this case, the terminal can be configured to perform power ramping between RACH attempts as before.

As a second proposed method, it can be defined that the UE can select a PRACH repetition resource corresponding to a specific RACH configuration (or a specific RACH partitioning) and then select a PRACH repetition resource corresponding to another RACH configuration (and/or another RACH partitioning) at a point in time when the UE has not yet performed all RACH attempts (i.e., when PREAMBLE_TRANSMISSION_COUNTER is not greater than preambleTransMax). In this case, the number of RACH attempts after which a different RACH configuration (or another RACH partitioning) can be selected can be set/indicated by the eNB through higher layer signaling (e.g., SIB1, etc.), or can be defined as a specific value in advance (e.g., re-selection possible for every RACH attempt). To be more specific, if the terminal fails to receive a RAR from the base station after performing a predefined/instructed number of RACH attempt transmissions, then the terminal may be allowed to select one of the RACH configurations (and/or specific RACH partitionings) having the same repetition number, regardless of the previously selected RACH configuration. In the above operation, the method for the terminal to set the PRACH transmit power may be as follows.

First, it can be configured so that the terminal continues the RACH procedure without changing the parameter values for counting the RACH attempt and/or the parameter values for counting power ramping used in the previous RACH procedure. That is, the terminal can be configured so that the terminal performs the RACH procedure in the newly selected RACH configuration (and/or RACH partitioning) while maintaining PREAMBLE_POWER_RAMPING_COUNTER, PREAMBLE_TRANSMISSION_COUNTER, etc. as they are. In this way, the terminal can perform the RACH procedure in the newly selected RACH configuration using the PRACH transmit power that is one step higher in power ramping than the PRACH transmit power transmitted in the previous RACH attempt. At this time, the PREAMBLE_POWER_RAMPING_STEP at which the terminal performs one-step power ramping can be configured to apply the value of the newly selected RACH configuration (and/or RACH partitioning).

Second, the terminal can be configured to initialize to 0 the parameter counting the RACH attempt used in the previous RACH procedure and/or the parameter counting the power ramping and perform the RACH procedure. That is, the PREAMBLE_POWER_RAMPING_COUNTER, PREAMBLE_TRANSMISSION_COUNTER, etc. can be initialized to 0 and the terminal can be configured to perform the RACH procedure in the newly selected RACH configuration (and/or RACH partitioning). In this case, the terminal can perform the RACH procedure using the initial PRACH transmit power defined in the newly selected RACH configuration, regardless of the PRACH transmit power value transmitted in the previous RACH attempt.

Third, the terminal can be configured to perform the RACH procedure by reducing the parameter values for counting RACH attempts and/or power rampings used in the previous RACH procedure by X and Y, respectively. At this time, the X and Y values can be independently set/indicated by the base station through higher layer signaling (e.g., SIB 1), or can be predefined values (e.g., X=1, Y=1). At this time, the base station can be defined to set the remaining parameter values to be the same as the instructed parameter values by instructing only the X value or only the Y value. That is, the PREAMBLE_TRANSMISSION_COUNTER, PREAMBLE_POWER_RAMPING_COUNTER, etc. can be set by reducing their existing values by X and Y, respectively, and the terminal can be configured to perform the RACH procedure in the newly selected RACH configuration (and/or RACH partitioning). For example, if X=1 and Y=1, the UE can perform the RACH procedure in the newly selected RACH configuration (and/or RACH partitioning) using the same PRACH transmit power value as the value transmitted in the previous RACH attempt.

Specifically, a method of maintaining PREAMBLE_TRANSMISSION_COUNTER and only decreasing PREAMBLE_POWER_RAMPING_COUNTER can be considered as a method to prevent the terminal from frequently and excessively changing the RACH configuration. That is, in the above example, X can be set to 0 and Y can be set to 1. If set this way, whenever the terminal changes the RACH configuration, the PRACH transmit power uses the same value as the PRACH transmit power value transmitted previously (i.e., transmit power ramping is not performed), and only the RACH attempt counter increases, making it difficult to reach the max PRACH transmit power, which in turn increases the RACH procedure failure probability of terminals that reselect the PRACH configuration excessively.

The proposed method can be configured/applied to other UL signal/channels such as MSG3 PUSCH, MSGA Preamble/PUSCH and/or PUSCH/PUCCH. Characteristically, the terminal/base station operation for the proposed PRACH repetition can also be configured/applied as the terminal/base station operation for other newly introduced features (e.g., repeated transmission feature of Msg. 4 HARQ ACK PUCCH). For example, the feature for PUCCH repetition (e.g., pucch-Repetitions-r18) can be configured/applied instead of the feature for the proposed PRACH repetition, and the feature for PUCCH repetition can be used for the proposed combination method and the method that the terminal does not expect. Furthermore, when the terminal/base station operation for PRACH repetition and/or PUCCH repetition are supported at the same time, the proposed methods can be configured/applied to both channels.

In addition, it is obvious that the examples of the proposed methods described above can also be included as one of the implementation methods of the present disclosure, and thus can be considered as a kind of proposed methods. In addition, the proposed methods described above can be implemented independently, but can be implemented in the form of a combination (or merge) of some of the proposed methods. Information on whether the proposed methods are applied (or information on rules of the proposed methods) can be defined as a rule so that the base station notifies the terminal through a predefined signal (e.g., a physical layer signal or a higher layer signal). The higher layer can include, for example, one or more of functional layers such as MAC, RLC, PDCP, RRC, and SDAP.

The methods, embodiments or descriptions for implementing the method proposed in the present disclosure may be applied separately, or one or more methods (or embodiments or descriptions) may be applied in combination.

[Terminal claim related explanation]

The embodiments described below are specifically described with reference to FIG. 6 in terms of the operation of a user equipment (UE). The methods described below are distinguished only for the convenience of explanation, and it goes without saying that some components of one method may be substituted for some components of another method, or may be applied in combination with each other, as long as they are not mutually exclusive.

FIG. 6 is a diagram illustrating an example of an operation process of a terminal in a system applicable to the present disclosure.

At step S610, the terminal receives RRC (radio resource control) information related to the maximum number of repetitions of a random access (RA) preamble corresponding to a first number from a base station (BS).

At step S620, the terminal performs a first repetition transmission of the RA preamble to the base station based on the first number of times in relation to the first RA procedure.

At step S630, if the first repetition transmission of the RA preamble based on the first number of times is performed and the first RA procedure is not completed, the terminal determines the number of repetition transmissions of the RA preamble based on a second number of times that is greater than the first number of times.

At step S640, the terminal performs a second repetition transmission of the RA preamble to the base station based on the second number of times in relation to the second RA procedure.

According to various embodiments of the present disclosure, when the first repetition transmission of the RA preamble corresponding to the first number of times is performed and a random access response (RAR) is received from the base station, the first RA procedure can be successfully completed.

According to various embodiments of the present disclosure, the embodiment of FIG. 6 may further include a step of determining RA resources corresponding to the second repeated transmission of the RA preamble based on the second number of times.

According to various embodiments of the present disclosure, the second RA procedure can be performed based on the RA resources.

According to various embodiments of the present disclosure, information of PREAMBLE_TRANSMISSION_COUNTER may be increased by 1 each time the RA preamble is transmitted to the base station.

According to various embodiments of the present disclosure, the change from the first number of times the RA preamble is repeated to the second number of times may be performed by the terminal.

According to various embodiments of the present disclosure, when the information of the PREAMBLE_TRANSMISSION_COUNTER corresponds to preambleTransMax + 1, all set numbers of RACH (random access channel) attempts can be performed.

According to various embodiments of the present disclosure, the preambleTransMax may correspond to a maximum number of RACH attempts.

According to various embodiments of the present disclosure, the second number of times can be determined based on a reference signal received power (RSRP) measurement.

According to various embodiments of the present disclosure, a terminal is provided in a wireless communication system. The terminal includes a transceiver and at least one processor, and the at least one processor can be configured to perform a method of operating the terminal according to FIG. 6.

According to various embodiments of the present disclosure, a device for controlling a terminal in a communication system is provided. The device includes at least one processor and at least one memory operably connected to the at least one processor. The at least one memory may be configured to store instructions for performing an operating method of the terminal according to FIG. 6 based on being executed by the at least one processor.

According to various embodiments of the present disclosure, one or more non-transitory computer readable media (CRM) storing one or more commands are provided. The one or more commands, based on being executed by one or more processors, perform operations, and the operations may include a method of operating a terminal according to FIG. 6.

[Explanation regarding base station claim]

The embodiments described below are specifically described with reference to FIG. 7 in terms of the operation of a base station (BS). The methods described below are distinguished only for the convenience of explanation, and it goes without saying that some components of one method may be substituted for some components of another method, or may be applied in combination with each other, as long as they are not mutually exclusive.

FIG. 7 is a diagram illustrating an example of an operation process of a base station in a system applicable to the present disclosure.

At step S710, the base station transmits radio resource control (RRC) information related to the maximum number of repetitions of a random access (RA) preamble corresponding to the first number to the user equipment (UE).

At step S720, the base station receives a first repetition transmission of the RA preamble from the terminal based on the first number of times in relation to the first RA procedure.

At step S730, the base station receives, in relation to a second RA procedure, a second repetition transmission of the RA preamble from the base station based on a second number of times, if the first repetition transmission of the RA preamble based on the first number of times is performed and the first RA procedure is not completed.

According to various embodiments of the present disclosure, the second number of times is a number of times the RA preamble is repeated more than the first number of times.

According to various embodiments of the present disclosure, when the first repetition transmission of the RA preamble corresponding to the first number of times is performed and a random access response (RAR) from the base station is received by the terminal, the first RA procedure can be successfully completed.

According to various embodiments of the present disclosure, information of PREAMBLE_TRANSMISSION_COUNTER may be increased by 1 each time the RA preamble is transmitted from the terminal to the base station.

According to various embodiments of the present disclosure, the change from the first number of times the RA preamble is repeated to the second number of times may be performed by the terminal.

According to various embodiments of the present disclosure, when the information of the PREAMBLE_TRANSMISSION_COUNTER corresponds to preambleTransMax + 1, all set numbers of RACH (random access channel) attempts can be performed.

According to various embodiments of the present disclosure, the preambleTransMax may correspond to a maximum number of RACH attempts.

According to various embodiments of the present disclosure, the second number of times can be determined based on a reference signal received power (RSRP) measurement.

According to various embodiments of the present disclosure, a base station is provided in a wireless communication system. The base station includes a transceiver and at least one processor, and the at least one processor can be configured to perform a method of operating the base station according to FIG. 7.

According to various embodiments of the present disclosure, a device for controlling a base station in a wireless communication system is provided. The device includes at least one processor and at least one memory operably connected to the at least one processor. The at least one memory may be configured to store instructions for performing a method of operating a base station according to FIG. 7 based on being executed by the at least one processor.

According to various embodiments of the present disclosure, one or more non-transitory computer readable media (CRM) storing one or more commands are provided. The one or more commands, when executed by one or more processors, perform operations, and the operations may include a method of operating a base station according to FIG. 7.

Wireless devices applicable to the present disclosure

Below, examples of wireless devices to which various embodiments of the present disclosure are applied are described.

FIG. 8 is a drawing illustrating an example of the structure of a first device and a second device in a system applicable to the present disclosure.

The first device (1600) may include a processor (1610), an antenna unit (1620), a transceiver (1630), and a memory (1640).

The processor (1610) performs baseband-related signal processing and may include an upper layer processing unit (1611) and a physical layer processing unit (1615). The upper layer processing unit (1611) may process operations of a MAC layer, an RRC layer, or higher layers. The physical layer processing unit (1615) may process operations of a PHY layer. For example, when the first device (1600) is a base station device in base station-terminal communication, the physical layer processing unit (1615) may perform uplink reception signal processing, downlink transmission signal processing, etc. For example, when the first device (1600) is a first terminal device in terminal-to-terminal communication, the physical layer processing unit (1615) may perform downlink reception signal processing, uplink transmission signal processing, sidelink transmission signal processing, etc. In addition to performing baseband-related signal processing, the processor (1610) may also control the overall operation of the first device (1600).

The antenna unit (1620) may include one or more physical antennas, and when it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (1630) may include an RF (Radio Frequency) transmitter and an RF receiver. The memory (1640) may store information processed by the processor (1610), and software, an operating system, applications, etc. related to the operation of the first device (1600), and may also include components such as a buffer.

The processor (1610) of the first device (1600) may be configured to implement operations of the base station in base station-to-terminal communication (or operations of the first terminal device in terminal-to-terminal communication) in the embodiments described in the present disclosure.

The second device (1650) may include a processor (1660), an antenna unit (1670), a transceiver (1680), and a memory (1690).

The processor (1660) performs baseband-related signal processing and may include an upper layer processing unit (1661) and a physical layer processing unit (1665). The upper layer processing unit (1661) may process operations of a MAC layer, an RRC layer, or higher layers. The physical layer processing unit (1665) may process operations of a PHY layer. For example, when the second device (1650) is a terminal device in base station-terminal communication, the physical layer processing unit (1665) may perform downlink reception signal processing, uplink transmission signal processing, etc. For example, when the second device (1650) is a second terminal device in terminal-to-terminal communication, the physical layer processing unit (1665) may perform downlink reception signal processing, uplink transmission signal processing, sidelink reception signal processing, etc. In addition to performing baseband-related signal processing, the processor (1660) may also control the overall operation of the second device (1660).

The antenna unit (1670) may include one or more physical antennas, and when it includes multiple antennas, it may support MIMO transmission and reception. The transceiver (1680) may include an RF transmitter and an RF receiver. The memory (1690) may store information processed by the processor (1660), and software, an operating system, applications, etc. related to the operation of the second device (1650), and may also include components such as a buffer.

The processor (1660) of the second device (1650) may be configured to implement operations of the terminal in base station-to-terminal communication (or operations of the second terminal device in terminal-to-terminal communication) in the embodiments described in the present disclosure.

In the operation of the first device (1600) and the second device (1650), the same explanations given for the base station and the terminal (or the first terminal and the second terminal in the terminal-to-terminal communication) in the examples of the present disclosure may be applied, and any duplicate explanations are omitted.

Here, the wireless communication technology implemented in the device (1600, 1650) of the present disclosure may include various other wireless communication technologies as well as LTE, NR, and 6G.

The claims described in the various embodiments of the present disclosure may be combined in various ways. For example, the technical features of the method claims of the various embodiments of the present disclosure may be combined and implemented as a device, and the technical features of the device claims of the various embodiments of the present disclosure may be combined and implemented as a method. In addition, the technical features of the method claims and the technical features of the device claims of the various embodiments of the present disclosure may be combined and implemented as a device, and the technical features of the method claims and the technical features of the device claims of the various embodiments of the present disclosure may be combined and implemented as a method.

Claims (20)

In a method of operating a terminal (user equipment, UE) in a wireless communication system, A step of receiving RRC (radio resource control) information related to a maximum number of repetitions of a RA (random access) preamble corresponding to a first number from a base station (BS); In relation to the first RA procedure, a step of performing a first repetition transmission of an RA preamble to the base station based on the first number of times; A step of determining the number of repetitions of the RA preamble based on a second number of times greater than the first number of times, when the first repetition transmission of the RA preamble is performed and the first RA procedure is not completed; In relation to the second RA procedure, the step of performing a second repetition transmission of the RA preamble to the base station based on the second number of times is included. method. In the first paragraph, When the first repetition transmission of the RA preamble corresponding to the first number of times is performed and a random access response (RAR) is received from the base station, the first RA procedure is successfully completed. method. In the first paragraph, Further comprising the step of determining RA resources corresponding to the second repeated transmission of the RA preamble based on the second number of times; The above second RA procedure is performed based on the above RA resources. method. In the first paragraph, Each time the above RA preamble is transmitted to the base station, the information in PREAMBLE_TRANSMISSION_COUNTER increases by 1. method. In the first paragraph, Regarding the number of repetitions of the above RA preamble, the change from the first number to the second number is performed by the terminal. method. In the fourth paragraph, If the information of the above PREAMBLE_TRANSMISSION_COUNTER corresponds to preambleTransMax + 1, all RACH (random access channel) attempts of the set number are performed. The above preambleTransMax corresponds to the maximum number of RACH attempts. method. In the first paragraph, The second number is determined based on the RSRP (reference signal received power) measurement. method. In a method of operating a base station (BS) in a wireless communication system, A step of transmitting RRC (radio resource control) information related to a maximum number of repetitions of a RA (random access) preamble corresponding to a first number to a user equipment (UE); In relation to the first RA procedure, a step of receiving a first repetition transmission of an RA preamble from the terminal based on the first number of times; If the first repetition transmission of the RA preamble based on the first number of times is performed and the first RA procedure is not completed, a step of receiving a second repetition transmission of the RA preamble from the base station based on the second number of times in relation to the second RA procedure is included. The second number of times is the number of times the RA preamble is repeated more than the first number of times. method. In Article 8, When the first repetition transmission of the RA preamble corresponding to the first number of times is performed and a random access response (RAR) from the base station is received by the terminal, the first RA procedure is successfully completed. method. In Article 8, The above second RA procedure is performed based on RA resources corresponding to the second repeated transmission of the RA preamble based on the second number of times. method. In Article 8, Each time the above RA preamble is transmitted from the terminal to the base station, the information of PREAMBLE_TRANSMISSION_COUNTER increases by 1. method. In Article 8, Regarding the number of repetitions of the above RA preamble, the change from the first number to the second number is performed by the terminal. method. In Article 11, If the information of the above PREAMBLE_TRANSMISSION_COUNTER corresponds to preambleTransMax + 1, all RACH (random access channel) attempts of the set number are performed. The above preambleTransMax corresponds to the maximum number of RACH attempts. method. In Article 8, The second number is determined based on the RSRP (reference signal received power) measurement. method. In a wireless communication system, at a terminal, Transmitter and receiver; at least one processor; and At least one memory operably connectable to said at least one processor and storing instructions that, when executed by said at least one processor, perform operations; The above actions are, Comprising all steps of a method according to any one of claims 1 to 7, Terminal. In a wireless communication system, at a base station, Transmitter and receiver; at least one processor; and At least one memory operably connectable to said at least one processor and storing instructions that, when executed by said at least one processor, perform operations; The above actions are, Comprising all steps of a method according to any one of claims 8 to 14, Base station. In a control device that controls a terminal in a wireless communication system, at least one processor; and comprising at least one memory operably connected to at least one of said processors; The at least one memory stores instructions for performing operations based on being executed by the at least one processor, The above actions are, Comprising all steps of a method according to any one of claims 1 to 7, controller. In a control device for controlling a base station in a wireless communication system, at least one processor; and comprising at least one memory operably connected to at least one of said processors; The at least one memory stores instructions for performing operations based on being executed by the at least one processor, The above actions are, Comprising all steps of a method according to any one of claims 8 to 14, controller. In one or more non-transitory computer-readable media storing one or more instructions, The one or more instructions perform operations based on being executed by one or more processors, The above actions are, Comprising all steps of a method according to any one of claims 1 to 7, Computer readable medium. In one or more non-transitory computer-readable media storing one or more instructions, The one or more instructions perform operations based on being executed by one or more processors, The above actions are, Comprising all steps of a method according to any one of claims 8 to 14, Computer readable medium.

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